Comparing Genotypic and Phenotypic Variation of Selfed and Outcrossed Progeny of Hemp

Abstract

<jats:p>Feminized hemp seed producers often use selfing to maintain a strain name; however, selfing may lead to inferior plants for cannabidiol (CBD) production. Using three different hemp strains as parents [Candida (CD-1), Dinamed CBD, and Abacus], two outcrosses [Candida (CD-1) × Abacus and Dinamed CBD × Candida (CD-1)] and one self-cross [Candida (CD-1) × Candida (CD-1)] were conducted to produce feminized seed. Progeny from the self-cross were significantly smaller and had less yield than outcrossed progeny. Selfed progeny were variegated and highly variable for total dry weight and floral dry weight. Discriminant analysis of principal components (DAPC) using amplified fragment length polymorphism (AFLP) separated the three progeny populations and showed that outcrossed populations clustered closer to the maternal parent, possibly the result of a maternal effect. Analysis of molecular variance (AMOVA) indicated that most variation (74.5%) was within populations, because the progeny from all three populations are half-siblings of each other. The selfed progeny population had lower expected heterozygosity (H<jats:sub>e</jats:sub> = 0.085) than each of the outcrossed progeny populations (H<jats:sub>e</jats:sub> ≈ 0.10). These results suggest that selfed progeny may demonstrate inbreeding depression resulting from enhanced expression of homozygous recessive traits. It may be beneficial for feminized seed producers to use outcrossing instead of selfing to generate feminized seed for CBD production.</jats:p>

Hemp Growth in Vitro and in Vivo: A Comparison of Growing Media and Growing Environments across 10 Accessions

“…The clear pattern of hybrids significantly outperforming nonhybrid selections in all parameters measured in vitro is consistent with observed patterns of heterosis in conventionally grown hemp (Kurtz et al, 2020). It should be noted that the 10 accessions evaluated do not come from the same parents, and that the classification of cultivars as hybrids and nonhybrid selections is rendered on the assumption that the mother plants, randomly selected for each cultivar, were representative of the cultivar's heterozygosity level.…”

“…This study aims to evaluate a combination of two nutrient media (MS and DKW) and two carbon sources (glucose and sucrose) in a step toward improving hemp micropropagation protocols. Furthermore, because heterosis has been documented in hemp field studies (Kurtz et al, 2020), we used a selection of genotypes expected to have different heterozygosity levels to explore the relationship between plant performance in vitro and in vivo. We hypothesized that DKW in combination with glucose would produce the most vigorous plantlets in vitro, and that vigor in vitro and in vivo would be correlated.…”

A Comparison of Two Media Formulations and Two Vented Culture Vessels for Shoot Multiplication and Rooting of Hemp Shoot Tip Cultures

“…'Abacus' is likely related to 'OG Kush', or plants derived from 'OG Kush', and 'Wife' appears to be derived from cannabidiol landrace plants (Phylos Bioscience Inc. 2022). 'Abacus' is noted for its compact form with dense branching, moderate growth rate, and anthocyanin development on stems and leaves (Kurtz et al 2020). 'Wife' is an upright spreading plant with a fast growth rate and green leaves.…”

Morphometric relationships and their contribution to biomass and cannabinoid yield in hybrids of hemp (Cannabis sativa)

“…This simple technique, pioneered by Ram and Sett (1982) , is effective and has changed little over time ( Lubell and Brand, 2018 ). Repeated cycles of self-pollination using this technique will lead to increased homozygosity and possible inbreeding depression ( Kurtz et al , 2020 ).…”